Results: Scientists at the Swiss Federal Institute of Tech­nology and the Chinese ­Academy of Sciences have used nonvolatile electrolytes and a new dye to improve the sta­bility of flexible dye-­sensitized solar cells (also called Grätzel cells) while achieving efficiencies of up to 10 percent.

Why it matters: Dye-­sensitized solar cells could be cheaper than conventional solar cells, because they’re made of inexpensive materials and can be printed rapidly. They can also be made flexible. But they have been difficult to manufacture and unreliable to operate, because the electrolytes that carry current within them are volatile and must be carefully encapsulated. By using nonvolatile electrolytes, the researchers have made Grätzel cells that are more reliable and potentially cheaper to manufacture. What’s more, the new dye allows the researchers to use the non­volatile electrolytes while maintaining efficiencies of near 10 percent, a level necessary to compete with conventional solar cells.

Method: The researchers coupled two previously synthesized nonvolatile electrolytes with a new dye that absorbs more light. That reduced both the amount of dye required and the thickness of the solar cells, making it easier for electrical charges to move out of the cell.

Next steps: The cells remain stable when exposed to light and high temperatures for 1,000 hours. The researchers are now testing them at higher temperatures, studying their long-term performance in a large solar panel, and working with corporate partners to commercialize the technology.